44 



THE WINGS 



[CH. 



We shall devote the remainder of this chapter to (1) a short 

 account of the development and histology of the wing in the larva, 

 and (2) phylogenetic studies of the principal features of the 

 imaginal wing. 



Fig. 17. Tracheation of the larval wing (to be used in conjunction with Plate II). 

 A Aeschna brevistyla Ramb.. fore -wing. B. The same, hind-wing, c. Hemi- 

 cordulia tau Selys, fore-whig, n. The same, hind-wing. E. Calopteryx 

 ipiendens Harris F. Austrolestes cingulatus Burm. G. Caliagrion bittinghursti 

 Martin. The lettering of the tracheae corresponds with that of the veins 

 which replace them in the imaginal wing. Original except B (drawn from 

 photograph sent by Dr F. Ris). 



